From: Sebastian Andrzej Siewior <bige...@linutronix.de>

kvmppc_alloc_host_rm_ops() holds get_online_cpus() while invoking
cpuhp_setup_state_nocalls().

cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
correct, but prevents the conversion of the hotplug locking to a percpu
rwsem.

Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested
call. Convert *_online_cpus() to the new interfaces while at it.

Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Cc: k...@vger.kernel.org
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: kvm-...@vger.kernel.org
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Alexander Graf <ag...@suse.com>

---
 arch/powerpc/kvm/book3s_hv.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3317,7 +3317,7 @@ void kvmppc_alloc_host_rm_ops(void)
                return;
        }
 
-       get_online_cpus();
+       cpus_read_lock();
 
        for (cpu = 0; cpu < nr_cpu_ids; cpu += threads_per_core) {
                if (!cpu_online(cpu))
@@ -3339,17 +3339,17 @@ void kvmppc_alloc_host_rm_ops(void)
        l_ops = (unsigned long) ops;
 
        if (cmpxchg64((unsigned long *)&kvmppc_host_rm_ops_hv, 0, l_ops)) {
-               put_online_cpus();
+               cpus_read_unlock();
                kfree(ops->rm_core);
                kfree(ops);
                return;
        }
 
-       cpuhp_setup_state_nocalls(CPUHP_KVM_PPC_BOOK3S_PREPARE,
-                                 "ppc/kvm_book3s:prepare",
-                                 kvmppc_set_host_core,
-                                 kvmppc_clear_host_core);
-       put_online_cpus();
+       cpuhp_setup_state_nocalls_cpuslocked(CPUHP_KVM_PPC_BOOK3S_PREPARE,
+                                            "ppc/kvm_book3s:prepare",
+                                            kvmppc_set_host_core,
+                                            kvmppc_clear_host_core);
+       cpus_read_unlock();
 }
 
 void kvmppc_free_host_rm_ops(void)


Reply via email to